Sensitive and Rapid Detection of Traditional Chinese Herbs by Loop-Mediated Isothermal Amplification Method and Real-Time Fluorescence Quantitative PCR

ABSTRACT Adulterant herbal materials are threats to import and export trade and consumer safety. In this study, we established a simple and rapid examination system for the detection of Phellodendron chinense Schneid. Two detection methods, real-time fluorescence quantitative PCR (real-time PCR) and loop-mediated isothermal amplification (LAMP), were developed for traditional Chinese medicine detection, and their specificity and sensitivity were compared. The DNA of P. chinense was extracted and its special periods amplified with designed primers. Real-time PCR and LAMP experiments were conducted to test the specificity of primers in contrast to other similar species. The template concentration was diluted from 101 ng/µL to 10-5 ng/µL in order to contrast sensitivity between real-time PCR and LAMP. Real-time PCR and Lamp method has shown specificity because P. chinense was positive as opposed to other negative similar species. The Lamp method could detect a limited DNA concentration of 10-4ng/µL in 60 minutes with same sensitivity to real-time PCR. The results indicate that real-time PCR and LAMP are sensitive, accurate and specific in detection of P. chinense. However, LAMP is more convenient and cast less time. What's more, expensive equipments are not necessary for LAMP detector. For a better detection, we suggest an establishment of a real-time PCR and LAMP method for TCM market supervision which depends on DNA barcode sequences and LAMP.

A novel approach to bar adsorptive microextraction: Cork as extractor phase for determination of benzophenone, triclocarban and parabens in aqueous samples.

This study describes the use of cork as a new coating for bar adsorptive microextraction (BAµE) and its application in determining benzophenone, triclocarban and parabens in aqueous samples by HPLC-DAD. In this study bars with 7.5 and 15 mm of length were used. The extraction and liquid desorption steps for BAµE were optimized employing multivariate and univariate procedures. The desorption time and solvent used for liquid desorption were optimized by univariate and multivariate studies, respectively. For the extraction step the sample pH was optimized by univariate experiments while the parameters extraction time and ionic strength were evaluated using the Doehlert design. The optimum extraction conditions were sample pH 5.5, NaCl concentration 25% and extraction time 90 min. Liquid desorption was carried out for 30 min with 250 µL (bar length of 15 mm) or 100 µL (bar length of 7.5 mm) of ACN:MeOH (50:50, v/v). The quantification limits varied between 1.6 and 20 µg L(-1) (bar length of 15 mm) and 0.64 and 8 µg L(-1) (bar length of 7.5 mm). The linear correlation coefficients were higher than 0.98 for both bars. The method with 7.5 mm bar length showed recovery values between 65 and 123%. The bar-to-bar reproducibility and the repeatability were lower than 13% (n = 2) and 14% (n = 3), respectively.